A Man Knocked Down His Basement Wall, Discovering Ancient Underground City That Housed 20,000 People (Video & Pictures)

The doors connecting each level were blocked by half-ton boulders only moveable from the inside that contained a small hole that allowed residents to spear the confined trespassers. Though it remains a mystery who the architects were, researchers believe the Hittites — a Bronze Age Anatolian people — may have excavated the first few levels in the rock when they came under attack from the Phrygians around 1200 BCE, A. Bertini, an expert in Mediterranean cave dwellings, wrote in his 2010 essay on regional cave architecture.